Weight loss advice?

3am weight thoughts really hit different don’t they?! In all seriousness I’m a college sophomore and I put on about 50 pounds from senior year to now. ( 50 was added at the end of freshman year and I have neither gained nor loss much since, my weight is still the same). Before college I was heavy into athletics. Soccer, baseball, and competitive track. I was really happy with my body. Skinny, built to an extent, just about to get those abs defined. Covid hit and college advice told me to drop athletics and pursue my degree. I jointed a fraternity and through all the wonderful parties I managed to drink, eat, and sit on my butt all the way to 200 pounds. I was 150-155 at the start of freshman year. I originally just increased activity to keep me from being a bum and gaining more weight, but I’m not losing. I’ve always ate like crap but I was always working it off in highschool. My girlfriend is even bummed I lost the body she used to love! I want to bring it back, for me and for her. My problem is I can’t find a workout to burn this “blubber” of fat, for me I really just want the visual fat gone and a flat stomach back. I also want to do a deficit and diet. Any workout and diet advice? I never lift weights in all honesty, my favorite workouts involve running and core workouts. Any ideas? Any help is incredibly appreciated. Thanks y’all!